Coatings

Abstract

This invention relates to coating a surface wherein the coated surface inhibits foulants such as cell and/or protein and/or prion adhesion or formation. In particular, the coated surface may be part of a medical device which inhibits bacterial adhesion and colonisation, thrombus formation and/or prion, blood protein and/or protein formation.

1. A modified surface wherein the adhesion or attachment of cells, proteins and/or prions to the modified surface has been minimised or prevented by adjusting the Lifshitz-van der Waals (LW) surface free energy of an unmodified surface to be equal to or approximately equal to the Lifshitz-van der Waals (LW) surface free energy of the cells, proteins and/or prions in a solution and/or whole blood surrounding the surface,
 wherein the surface is modified with a coating of modified diamond-like carbon (DLC), 
 wherein the coated surface inhibits bacterial adhesion and colonisation, thrombus adhesion to the surface and foulant formation, 
 wherein the surface is one which comes into contact with cells, proteins and/or prions within a living human or animal body, 
 wherein the LW surface free energy of the modified surface is in a range of about 25 mN/m to about 45 mN/m, and 
 wherein the adhesion or attachment of said cells, proteins and/or prions is minimised or prevented by modifying the surface free energy γ LW   surface  of the surface in accordance with the Lifshitz-van der Waals (LW) surface free energy of the cells, proteins and/or prions so that:
   γ LW   surface≈γ   LW   S,Min  
 
 
 
       wherein γ LW   S,Min  is the minimum level of attachment to a surface S and is defined as follows:
   √{square root over (γ LW   S,Min )}=(½)(√{square root over (γ LW   cells and/or proteins and/or prions )}+√{square root over (γ LW   solution and/or whole blood )})
 
 where  γ   LW   cells, proteins and/or prions  is the LW surface free energy of the cells, proteins and/or prions, and  γ   LW   solution and/or whole blood  is the LW surface free energy of the solution and/or of whole blood. 
 
     
     
       2. A modified surface according to  claim 1  wherein the surface is modified with a coating of diamond-like carbon (DLC) which is modified by incorporating elements selected from any of the following: halogens; Group IV elements; Group V elements;
 Group VI elements; and transition metals. 
 
     
     
       3. A modified surface according to  claim 2  wherein the elements are present in an amount of 0-40% by weight. 
     
     
       4. A modified surface according to  claim 2  wherein the elements incorporated into the diamond-like carbon by co-sputtering. 
     
     
       5. A modified surface according to  claim 2  wherein the elements are incorporated into the diamond-like carbon (DLC) using reactive gases, silicon organic monomers, gaseous hydrocarbons, O 2 , and/or N 2 . 
     
     
       6. A modified surface according to  claim 1  wherein the modified diamond-like carbon (DLC) is deposited using any of the following methods: microwave plasma deposition, plasma-enhanced vapour deposition, plasma-induced cold deposition, magnetron sputtering and ion beam-assisted deposition. 
     
     
       7. A modified surface according to  claim 1  wherein the modified surface is part of a medical device. 
     
     
       8. A modified surface according to  claim 7  wherein the medical device is selected from any of the following: endoscopes and accessories; ophthalmic equipment; dental equipment; surgical instruments; heart valves; stents; catheters; joint prostheses; intraocular lenses, dental implants, electrodes and cable equipment. 
     
     
       9. A modified surface according to  claim 1  wherein the modified surface inhibits the following bacteria:  Staphylococcus epidermidis, Staphylococcus aureus, Psuedomonas aeruginosa, Escherichia coli, Candida albicans  or any other microorganisms which could cause device-related infections. 
     
     
       10. A device comprising a modified surface according to  claim 1 .